Method and apparatus for forming, compacting, and discharging filter cake



Nov. 6, 1934. I: w; NKEWTON El AL 1,979,991

METHOD AND APPARATUS FOR FORMING, COMPACTING, AND D ISCHARGING FILTER CAKE Filed Sept. 19; 1931 Atto r2395 Patented Nov. 6, 1934 UNITED twain METHOD AND APPARATUS FOR FORMING,

CGMPACTING, CAKE AND DllSCI-IARGING FILTER Harry W. Newton, Chicago, IlL, and Robert S.

Butler, Los Angeles, Calif., assignors to Nordberg Manufacturing (30., Milwaukee, Wis.,' a corporation of Wisconsin Application September 19, 1931, Serial No. 563,724

1 Claim.

Our invention relates to a method of and apparatus for forming and discharging :filter cakes. One object is the provision of improvedmeans and method for discharging said cake by mechanical vibration. Other objects will appear from time to time in the course of the specification and claim. 7

We illustrate our invention more or less diagrammatically in the accompanying drawing, wherein Figure 1 is a side elevation;

Figure 2 is a section on the line 2-2 of Figure 1; and

Figure 3 is a section on the line 33 of Figv ure 2.

Like parts are indicated by like symbols throughout the specification and drawing.

Referring to the drawing, A indicates any suitable basefrom which upwardly extend sup- 0 ports A upon which are indicated brackets A A The brackets A support bearing sleeves A and the brackets A support corresponding bearing sleeves. 1

Mounted in any suitable manner on the sup- 5 ports A as by the cross members B, is a vacuum chamber having an upper portion 33 and a lower portion B 18 B indicate one: or more passages in communication with said vacuum chambers and B indicates a line extending to 0 any suitable exhausting means," not herein shown, whereby a suction may be maintained in the chambers 13 B The chambers are ported as at B As will be seen in Figure 2, the upper surface of the chamber B and the lower surface 85 of the chamber B is formed by the wall 13 in which are the ports B This wall maybe covered by a fiat rubber valve seat 13 ported as at B in communication with the ports B The wall 2B and the valve seat'B include upper 40 and lower rectilinear portions connected at the ends by arcuate'portion's as shown in Figure 1. Preferably the ports 18 and B are omitted from that portion or" the wall B and valve seat 13' which connect the right hand ends of the rectilinear portions of said walls, referring to the position of the parts as shown in Figure 1. In other words the ports B B extend throughout most of the length of the valve seat so formed, but are interrupted at the right hand end of the device.

"7&5 by a tube C in communication with the interior of the filter leaf structure 0*, the walls of which are closed by the septum 0 It will be understood that any desired number of these valve leaves may be mounted on the rubber valve band and that they move with the band, in a closed path across the valve seat B It will further be understood that the coupling, 0 is aligned with the apertures B B? whereby, as the rubber valve band C is moved, suctionis maintained in the interior of the filter leaf 0*. In. other Words, air is drawn through the septum C the passage C the coupling C and the aperture C to the chamber B or B gwhence it may be exhausted through the line B The suction may be intermittent but preferably the parts are so proportioned that a constant suction is maintained, the diameter of the passage C having such relation to the apertures 13 B that it is always in communication with at least one of them.

We may employ any suitable means for moving the valve band and the leaves. We illustrate for example the drive shaft D mounted for rotation in the bearings A and provided with a sprocket D whence the shaft may be rotated from any suitable power source not herein shown. The shaft D also carries sprocketsD having the teeth D meshing with chains D? which are connected by cross-pieces D from which extend arms D to which the filter leaves C are secured. The cross-pieces D may also communicate with or support or be in connection with the couplings C and are also secured to the rubber valve band C. Therefore, when the shaft D is rotated the chains D travel around the sprockets D and carry with them the filter leaves C and the rubber valve band C. D is any suitable shaft mounted at the opposite end of the device on the bracketA which carries smaller sprockets D about which pass the chains D 7 E indicates diagrammatically .anysuitable container or means for maintaining or providing a supply of the liquid to be filtered. The device is driven in the direction of the arrow of Figure 1 with individual filter leaves passing through the liquid E in the container E. As suction is maintained, the liquid is drawn against the septum walls C The water or liquid content is drawn through the septum, Whereas the solids are caught on the outer faces of the septum and form a filter cake. Such a cake, as it forms, contains a very substantial liquid content. As the rotation of the device continues, the individual filter leaves are withdrawn from the liquid E and suction is maintained, holding the cake in place on the septum. An important phase of our invention is the consolidation of such cake, after the filter leaf has been withdrawn from the liquid being filtered. We find it highly effective to vibrate the individual filter leaves, while maintaining them under suction to hold the cake in place. As an example of means for vibrating the leaves we illustrate the sleeve G which is shown as loose on the shaft D and driven from any suitable power source by the sprocket G The sleeve G includes a cam G having camming irregularities G of any suitable shape, size and number. G generally indicates an impact delivering-lever which is pivoted intermediate its ends as at G. The lower arm G6 is contacted by the cam members G The upper arm G" includes a contact portion Gr adapted to tap an opposed contact portion G associated with the side of the individual filter leavesC The contact portions G are herein indicated as in the form of laterally extending members which bridge the space between several individual filter leaves, whereby two or more of the said leaves may be simultaneously vibrated by the vibration of an individual lever G. We may employseveral of the vibrating levers G actuated by the disc (3? and extending radially from it. We may also employ an additional lever or levers G vibrated from a corresponding disc G adjacent the opposite end of the device.

It will be understood that the suction is maintained on the leaves up to the time they reach the point indicated as X in Figure 1. The suction is then broken and is not resumed until the leaf reaches the point marked Y in Figure 1. As the individual leaves pass beyond the last of the contact members G8 extending above the upper portion of the filter the vibration ceases and at the same time or shortly thereafter the suction is cut off. The leaves then pass about the are at the right hand end of the device until they come in contact with the lower vibrating member G which engages them after the suction is cut off and at a time when the leaves are downwardly inclined. The vibration delivered thereby is for the purpose of freeing or discharging the now compacted cake and we find. that the cake readily drops from the leaf and may be received in any suitable manner for example in the container generally indicated as H. Then the individual filter leaf, freed from the cake, again enters the suction zone and passes beneath the surface of the liquid E to gather another filter cake which, in turn, is first compacted by vibration, under suction, is then relieved from the suction, and finally, is again freed by renewed vibration.

It will be realized that whereas we have described and shown a practical and operative device, nevertheless many changes may be made in size, shape, number and disposition of parts without departing from the spirit of our invention. We therefore wish our description and drawing to be taken as in a broad sense illustrative and diagrammatic rather than as limiting us to our specific showing.

The use and operation of our invention are as follows:

In the formation and removal of filter cakes various means have been employed for removing the cake after its formation, and for reducing the water content. In our method and mechanism we provide means for first forming a cake on a septum or pervious member. Then the cake, which may be a very thin cake, is compacted by vibration of the members G which impart their vibration to the leaves. Then, after the individual leaves pass the point X, as an example, the suction is cut off. As the leaves continue their movement further they enter a second zone of vibration. In the device as herein shown this second zone does not begin until the leaves are downwardly inclined. Hence the cake as it is freed from the septum will drop down into the container H. We find that after the cake is compacted as above described and after the suction is taken off, the rapid vibration of the individual filter leaves very readily and, completely frees the cake. The cake so produced is thin and dry. However, the thickness of the cake may be greatly varied, depending upon the liquid treated, the speed of the belt, the length of time the individual leaves are in the liquid, etc. However, we can form and discharge a very thin and very dry cake. The cake, when discharged, leaves the septum clean as contrasted for example to the methods and apparatus wherein a relatively wet cake is scraped from a septum. Furthermore, since there is no scraping or physical impact against the face of the septum itself, the wear of the filter leaves is greatly reduced.

We claim:

The method of forming and discharging a filter cake, which includes subjecting a septum to the liquid to be filtered and forming the cake upon said septum, removing septum and cake from contact with the liquid, maintaining a suction through cake and septum after the removal from the liquid, subjecting cake and septum as a whole, after such removal and during such suction, to positive bodily oscillation of an amplitude and frequency sufficient to cause a substantial regrouping of the solid particles of the cake, terminating said suction, and thereafter subjecting the cake and septum to further positive bodily oscillation, and thereby discharging the cake from the septum, the positive bodily oscillation being propagated generally in the plane of the septum.

. HARRY W. NEWTON. ROBERT S. BUTLER. 

